Commit 49317a7f authored by NeilBrown's avatar NeilBrown Committed by Trond Myklebust
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NFS: nfs4_lookup_revalidate: only evaluate parent if it will be used. 



nfs4_lookup_revalidate only uses 'parent' to get 'dir', and only
uses 'dir' if 'inode == NULL'.

So we don't need to find out what 'parent' or 'dir' is until we
know that 'inode' is NULL.

By moving 'dget_parent' inside the 'if', we can reduce the number of
call sites for 'dput(parent)'.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 1f70ef96

fs/nfs/dir.c

+8 −9
Original line number Diff line number Diff line
@@ -1529,9 +1529,7 @@ EXPORT_SYMBOL_GPL(nfs_atomic_open); 


static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)

{

	struct dentry *parent = NULL;

	struct inode *inode;

	struct inode *dir;

	int ret = 0;



	if (flags & LOOKUP_RCU)
@@ -1545,34 +1543,35 @@ static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) 
		goto no_open;



	inode = dentry->d_inode;

	parent = dget_parent(dentry);

	dir = parent->d_inode;



	/* We can't create new files in nfs_open_revalidate(), so we

	 * optimize away revalidation of negative dentries.

	 */

	if (inode == NULL) {

		struct dentry *parent;

		struct inode *dir;



		parent = dget_parent(dentry);

		dir = parent->d_inode;

		if (!nfs_neg_need_reval(dir, dentry, flags))

			ret = 1;

		dput(parent);

		goto out;

	}



	/* NFS only supports OPEN on regular files */

	if (!S_ISREG(inode->i_mode))

		goto no_open_dput;

		goto no_open;

	/* We cannot do exclusive creation on a positive dentry */

	if (flags & LOOKUP_EXCL)

		goto no_open_dput;

		goto no_open;



	/* Let f_op->open() actually open (and revalidate) the file */

	ret = 1;



out:

	dput(parent);

	return ret;



no_open_dput:

	dput(parent);

no_open:

	return nfs_lookup_revalidate(dentry, flags);

}

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